Foamy Virus Vectors

Abstract

Successful treatment for diseases such as cancer and AIDS will likely involve particular combinations of drug therapy, immunotherapy, and gene therapy. Gene therapy is a novel approach currently under development for treatment of a variety of diseases (Anderson 1998). This novel therapy offers a fresh alternative, which endows a therapeutic effect by introduction of a particular gene into targeted cells. The effect of gene therapy in the host will depend, in part, on the efficiency of the vector system used to deliver the effector molecule. Numerous vector constructions have been used to deliver and express genes in human cells. Biological vectors for gene therapy are constructed from several viruses that include herpes simplex virus type 1, adenovirus, adenoassociated virus, and retroviruses (Kay et al. 2001; Robbins et al. 1998; Romano et al. 2000; Smith 1999; Wolfe et al. 1999; Wu and Ataai 2000). Among these vectors, retroviruses are most widely used as an efficient means for introducing foreign DNA into the cell genome. The life cycle of retroviruses involves stable integration of viral genetic material into the host genome; expression of viral genes is, in part, regulated by host cell factors (Coffin et al. 1997). These features of retroviruses make them useful for selected applications of gene transfer in animals and humans. Retroviral vectors are significant for basic biological investigations such as studies of cell lineage, mechanisms of carcinogenesis, and developmental and tissue-specific regulation of defined DNA sequences as well as clinical uses for gene therapy (Varmus 1988). Clinical applications of retroviral